| 학회 | 한국재료학회 |
| 학술대회 | 2016년 봄 (05/18 ~ 05/20, 여수 디오션리조트 ) |
| 권호 | 22권 1호 |
| 발표분야 | E. 환경/센서 재료분과 |
| 제목 | High-yield deterministic assembly of nanowire arrays for on-chip sensing applications |
| 초록 | Bottom-up integration of batch-synthesized nanowires with silicon CMOS circuitry represents a significant step toward future miniaturized multi-functional chips with chemical diversity. Spa-tially-confined electric field forces have been used previously to position individual nanowires in high density arrays with submicron registration accuracy to lithographic features on the chip. This presentation will discuss an experimental and theoretical study that quantifies the long-range dielectrophoretic forces and shorter-range electrostatic forces that govern this deterministic nanowire assembly process. It will also provide a practical example that shows the chip-based integration of conducting polymer nanowire sensor arrays. The nanowire array assembly study used features that were designed to modify the electric field intensity and its spatial profile across the silicon chip. Initial experiments were conducted with pairs of metal electrodes separated by a narrow gap and coated with a thin dielectric layer. When an AC bias is applied between adjacent pairs of electrodes, an intense and uniform electric field is observed along the edges of the metal electrodes. This creates a long-range dielectrophoretic force that attracts and orients the polarized nanowires to span the narrow gap. Electrostatic inter-actions between the neighboring nanowires as well as the nanowires and the electrodes cause the nanowires to organize into a uniformly spaced array in which each nanowire is centered across the gap. The minimum spacing depends on many factors including the electric field intensity, nanowire length, and conductivity. A typical spacing for 7 m long, 250 nm diameter Rh wires is ~5 m. Although this structure provides uniform, oriented nanowire arrays, it lacks accurate registration to features on the chip. To overcome this limitation, the electric field intensity was increased in specific positions along the electrode gap by adding an array of 2 m wide wells on top of the first dielectric layer. Ex-periments confirmed that the increased field intensity, and hence dielectrophoretic force, results in preferential assembly of individual nanowires within the wells. Individual nanowire assembly yields exceeding 95% were obtained at Rh nanowire densities ＞106 cm-2. This deterministic as-sembly process was used to fabricate arrays of electrically-contacted conducting polymer (e.g., PEDOT/PSS) nanowire chemical sensors. A histogram showing the chemical sensing response of over 50 individual nanowire sensors to three different volatile organic compounds will also be presented. |
| 저자 | 김재균 |
| 소속 | 한밭대 |
| 키워드 | <P>Dielectrophoresis; Nanowire; Chemical sensor</P> |
